![Krzysztof Kozlowski](/assets/img/avatar_default.png)
The dma-mapping core and the implementations do not change the DMA attributes passed by pointer. Thus the pointer can point to const data. However the attributes do not have to be a bitfield. Instead unsigned long will do fine: 1. This is just simpler. Both in terms of reading the code and setting attributes. Instead of initializing local attributes on the stack and passing pointer to it to dma_set_attr(), just set the bits. 2. It brings safeness and checking for const correctness because the attributes are passed by value. Semantic patches for this change (at least most of them): virtual patch virtual context @r@ identifier f, attrs; @@ f(..., - struct dma_attrs *attrs + unsigned long attrs , ...) { ... } @@ identifier r.f; @@ f(..., - NULL + 0 ) and // Options: --all-includes virtual patch virtual context @r@ identifier f, attrs; type t; @@ t f(..., struct dma_attrs *attrs); @@ identifier r.f; @@ f(..., - NULL + 0 ) Link: http://lkml.kernel.org/r/1468399300-5399-2-git-send-email-k.kozlowski@samsung.com Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Acked-by: Vineet Gupta <vgupta@synopsys.com> Acked-by: Robin Murphy <robin.murphy@arm.com> Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> Acked-by: Mark Salter <msalter@redhat.com> [c6x] Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> [cris] Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> [drm] Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Acked-by: Joerg Roedel <jroedel@suse.de> [iommu] Acked-by: Fabien Dessenne <fabien.dessenne@st.com> [bdisp] Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> [vb2-core] Acked-by: David Vrabel <david.vrabel@citrix.com> [xen] Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [xen swiotlb] Acked-by: Joerg Roedel <jroedel@suse.de> [iommu] Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon] Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k] Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390] Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org> Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> [avr32] Acked-by: Vineet Gupta <vgupta@synopsys.com> [arc] Acked-by: Robin Murphy <robin.murphy@arm.com> [arm64 and dma-iommu] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
586 lines
17 KiB
C
586 lines
17 KiB
C
/*
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* A fairly generic DMA-API to IOMMU-API glue layer.
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*
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* Copyright (C) 2014-2015 ARM Ltd.
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*
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* based in part on arch/arm/mm/dma-mapping.c:
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* Copyright (C) 2000-2004 Russell King
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/device.h>
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#include <linux/dma-iommu.h>
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#include <linux/gfp.h>
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#include <linux/huge_mm.h>
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#include <linux/iommu.h>
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#include <linux/iova.h>
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#include <linux/mm.h>
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#include <linux/scatterlist.h>
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#include <linux/vmalloc.h>
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int iommu_dma_init(void)
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{
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return iova_cache_get();
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}
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/**
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* iommu_get_dma_cookie - Acquire DMA-API resources for a domain
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* @domain: IOMMU domain to prepare for DMA-API usage
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*
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* IOMMU drivers should normally call this from their domain_alloc
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* callback when domain->type == IOMMU_DOMAIN_DMA.
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*/
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int iommu_get_dma_cookie(struct iommu_domain *domain)
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{
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struct iova_domain *iovad;
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if (domain->iova_cookie)
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return -EEXIST;
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iovad = kzalloc(sizeof(*iovad), GFP_KERNEL);
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domain->iova_cookie = iovad;
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return iovad ? 0 : -ENOMEM;
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}
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EXPORT_SYMBOL(iommu_get_dma_cookie);
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/**
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* iommu_put_dma_cookie - Release a domain's DMA mapping resources
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* @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
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*
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* IOMMU drivers should normally call this from their domain_free callback.
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*/
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void iommu_put_dma_cookie(struct iommu_domain *domain)
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{
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struct iova_domain *iovad = domain->iova_cookie;
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if (!iovad)
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return;
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put_iova_domain(iovad);
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kfree(iovad);
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domain->iova_cookie = NULL;
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}
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EXPORT_SYMBOL(iommu_put_dma_cookie);
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/**
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* iommu_dma_init_domain - Initialise a DMA mapping domain
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* @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
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* @base: IOVA at which the mappable address space starts
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* @size: Size of IOVA space
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*
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* @base and @size should be exact multiples of IOMMU page granularity to
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* avoid rounding surprises. If necessary, we reserve the page at address 0
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* to ensure it is an invalid IOVA. It is safe to reinitialise a domain, but
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* any change which could make prior IOVAs invalid will fail.
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*/
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int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, u64 size)
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{
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struct iova_domain *iovad = domain->iova_cookie;
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unsigned long order, base_pfn, end_pfn;
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if (!iovad)
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return -ENODEV;
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/* Use the smallest supported page size for IOVA granularity */
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order = __ffs(domain->pgsize_bitmap);
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base_pfn = max_t(unsigned long, 1, base >> order);
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end_pfn = (base + size - 1) >> order;
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/* Check the domain allows at least some access to the device... */
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if (domain->geometry.force_aperture) {
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if (base > domain->geometry.aperture_end ||
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base + size <= domain->geometry.aperture_start) {
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pr_warn("specified DMA range outside IOMMU capability\n");
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return -EFAULT;
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}
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/* ...then finally give it a kicking to make sure it fits */
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base_pfn = max_t(unsigned long, base_pfn,
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domain->geometry.aperture_start >> order);
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end_pfn = min_t(unsigned long, end_pfn,
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domain->geometry.aperture_end >> order);
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}
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/* All we can safely do with an existing domain is enlarge it */
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if (iovad->start_pfn) {
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if (1UL << order != iovad->granule ||
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base_pfn != iovad->start_pfn ||
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end_pfn < iovad->dma_32bit_pfn) {
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pr_warn("Incompatible range for DMA domain\n");
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return -EFAULT;
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}
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iovad->dma_32bit_pfn = end_pfn;
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} else {
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init_iova_domain(iovad, 1UL << order, base_pfn, end_pfn);
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}
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return 0;
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}
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EXPORT_SYMBOL(iommu_dma_init_domain);
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/**
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* dma_direction_to_prot - Translate DMA API directions to IOMMU API page flags
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* @dir: Direction of DMA transfer
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* @coherent: Is the DMA master cache-coherent?
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*
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* Return: corresponding IOMMU API page protection flags
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*/
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int dma_direction_to_prot(enum dma_data_direction dir, bool coherent)
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{
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int prot = coherent ? IOMMU_CACHE : 0;
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switch (dir) {
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case DMA_BIDIRECTIONAL:
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return prot | IOMMU_READ | IOMMU_WRITE;
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case DMA_TO_DEVICE:
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return prot | IOMMU_READ;
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case DMA_FROM_DEVICE:
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return prot | IOMMU_WRITE;
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default:
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return 0;
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}
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}
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static struct iova *__alloc_iova(struct iova_domain *iovad, size_t size,
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dma_addr_t dma_limit)
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{
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unsigned long shift = iova_shift(iovad);
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unsigned long length = iova_align(iovad, size) >> shift;
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/*
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* Enforce size-alignment to be safe - there could perhaps be an
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* attribute to control this per-device, or at least per-domain...
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*/
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return alloc_iova(iovad, length, dma_limit >> shift, true);
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}
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/* The IOVA allocator knows what we mapped, so just unmap whatever that was */
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static void __iommu_dma_unmap(struct iommu_domain *domain, dma_addr_t dma_addr)
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{
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struct iova_domain *iovad = domain->iova_cookie;
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unsigned long shift = iova_shift(iovad);
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unsigned long pfn = dma_addr >> shift;
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struct iova *iova = find_iova(iovad, pfn);
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size_t size;
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if (WARN_ON(!iova))
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return;
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size = iova_size(iova) << shift;
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size -= iommu_unmap(domain, pfn << shift, size);
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/* ...and if we can't, then something is horribly, horribly wrong */
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WARN_ON(size > 0);
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__free_iova(iovad, iova);
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}
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static void __iommu_dma_free_pages(struct page **pages, int count)
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{
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while (count--)
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__free_page(pages[count]);
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kvfree(pages);
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}
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static struct page **__iommu_dma_alloc_pages(unsigned int count,
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unsigned long order_mask, gfp_t gfp)
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{
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struct page **pages;
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unsigned int i = 0, array_size = count * sizeof(*pages);
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order_mask &= (2U << MAX_ORDER) - 1;
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if (!order_mask)
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return NULL;
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if (array_size <= PAGE_SIZE)
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pages = kzalloc(array_size, GFP_KERNEL);
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else
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pages = vzalloc(array_size);
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if (!pages)
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return NULL;
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/* IOMMU can map any pages, so himem can also be used here */
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gfp |= __GFP_NOWARN | __GFP_HIGHMEM;
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while (count) {
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struct page *page = NULL;
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unsigned int order_size;
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/*
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* Higher-order allocations are a convenience rather
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* than a necessity, hence using __GFP_NORETRY until
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* falling back to minimum-order allocations.
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*/
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for (order_mask &= (2U << __fls(count)) - 1;
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order_mask; order_mask &= ~order_size) {
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unsigned int order = __fls(order_mask);
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order_size = 1U << order;
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page = alloc_pages((order_mask - order_size) ?
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gfp | __GFP_NORETRY : gfp, order);
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if (!page)
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continue;
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if (!order)
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break;
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if (!PageCompound(page)) {
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split_page(page, order);
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break;
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} else if (!split_huge_page(page)) {
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break;
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}
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__free_pages(page, order);
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}
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if (!page) {
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__iommu_dma_free_pages(pages, i);
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return NULL;
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}
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count -= order_size;
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while (order_size--)
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pages[i++] = page++;
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}
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return pages;
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}
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/**
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* iommu_dma_free - Free a buffer allocated by iommu_dma_alloc()
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* @dev: Device which owns this buffer
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* @pages: Array of buffer pages as returned by iommu_dma_alloc()
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* @size: Size of buffer in bytes
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* @handle: DMA address of buffer
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*
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* Frees both the pages associated with the buffer, and the array
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* describing them
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*/
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void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
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dma_addr_t *handle)
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{
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__iommu_dma_unmap(iommu_get_domain_for_dev(dev), *handle);
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__iommu_dma_free_pages(pages, PAGE_ALIGN(size) >> PAGE_SHIFT);
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*handle = DMA_ERROR_CODE;
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}
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/**
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* iommu_dma_alloc - Allocate and map a buffer contiguous in IOVA space
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* @dev: Device to allocate memory for. Must be a real device
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* attached to an iommu_dma_domain
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* @size: Size of buffer in bytes
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* @gfp: Allocation flags
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* @attrs: DMA attributes for this allocation
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* @prot: IOMMU mapping flags
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* @handle: Out argument for allocated DMA handle
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* @flush_page: Arch callback which must ensure PAGE_SIZE bytes from the
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* given VA/PA are visible to the given non-coherent device.
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*
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* If @size is less than PAGE_SIZE, then a full CPU page will be allocated,
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* but an IOMMU which supports smaller pages might not map the whole thing.
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*
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* Return: Array of struct page pointers describing the buffer,
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* or NULL on failure.
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*/
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struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
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unsigned long attrs, int prot, dma_addr_t *handle,
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void (*flush_page)(struct device *, const void *, phys_addr_t))
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{
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struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
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struct iova_domain *iovad = domain->iova_cookie;
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struct iova *iova;
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struct page **pages;
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struct sg_table sgt;
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dma_addr_t dma_addr;
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unsigned int count, min_size, alloc_sizes = domain->pgsize_bitmap;
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*handle = DMA_ERROR_CODE;
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min_size = alloc_sizes & -alloc_sizes;
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if (min_size < PAGE_SIZE) {
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min_size = PAGE_SIZE;
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alloc_sizes |= PAGE_SIZE;
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} else {
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size = ALIGN(size, min_size);
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}
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if (attrs & DMA_ATTR_ALLOC_SINGLE_PAGES)
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alloc_sizes = min_size;
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count = PAGE_ALIGN(size) >> PAGE_SHIFT;
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pages = __iommu_dma_alloc_pages(count, alloc_sizes >> PAGE_SHIFT, gfp);
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if (!pages)
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return NULL;
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iova = __alloc_iova(iovad, size, dev->coherent_dma_mask);
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if (!iova)
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goto out_free_pages;
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size = iova_align(iovad, size);
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if (sg_alloc_table_from_pages(&sgt, pages, count, 0, size, GFP_KERNEL))
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goto out_free_iova;
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if (!(prot & IOMMU_CACHE)) {
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struct sg_mapping_iter miter;
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/*
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* The CPU-centric flushing implied by SG_MITER_TO_SG isn't
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* sufficient here, so skip it by using the "wrong" direction.
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*/
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sg_miter_start(&miter, sgt.sgl, sgt.orig_nents, SG_MITER_FROM_SG);
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while (sg_miter_next(&miter))
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flush_page(dev, miter.addr, page_to_phys(miter.page));
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sg_miter_stop(&miter);
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}
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dma_addr = iova_dma_addr(iovad, iova);
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if (iommu_map_sg(domain, dma_addr, sgt.sgl, sgt.orig_nents, prot)
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< size)
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goto out_free_sg;
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*handle = dma_addr;
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sg_free_table(&sgt);
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return pages;
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out_free_sg:
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sg_free_table(&sgt);
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out_free_iova:
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__free_iova(iovad, iova);
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out_free_pages:
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__iommu_dma_free_pages(pages, count);
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return NULL;
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}
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/**
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* iommu_dma_mmap - Map a buffer into provided user VMA
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* @pages: Array representing buffer from iommu_dma_alloc()
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* @size: Size of buffer in bytes
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* @vma: VMA describing requested userspace mapping
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*
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* Maps the pages of the buffer in @pages into @vma. The caller is responsible
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* for verifying the correct size and protection of @vma beforehand.
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*/
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int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma)
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{
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unsigned long uaddr = vma->vm_start;
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unsigned int i, count = PAGE_ALIGN(size) >> PAGE_SHIFT;
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int ret = -ENXIO;
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for (i = vma->vm_pgoff; i < count && uaddr < vma->vm_end; i++) {
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ret = vm_insert_page(vma, uaddr, pages[i]);
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if (ret)
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break;
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uaddr += PAGE_SIZE;
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}
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return ret;
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}
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dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
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unsigned long offset, size_t size, int prot)
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{
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dma_addr_t dma_addr;
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struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
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struct iova_domain *iovad = domain->iova_cookie;
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phys_addr_t phys = page_to_phys(page) + offset;
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size_t iova_off = iova_offset(iovad, phys);
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size_t len = iova_align(iovad, size + iova_off);
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struct iova *iova = __alloc_iova(iovad, len, dma_get_mask(dev));
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if (!iova)
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return DMA_ERROR_CODE;
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dma_addr = iova_dma_addr(iovad, iova);
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if (iommu_map(domain, dma_addr, phys - iova_off, len, prot)) {
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__free_iova(iovad, iova);
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return DMA_ERROR_CODE;
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}
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return dma_addr + iova_off;
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}
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void iommu_dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size,
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enum dma_data_direction dir, unsigned long attrs)
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{
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__iommu_dma_unmap(iommu_get_domain_for_dev(dev), handle);
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}
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/*
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* Prepare a successfully-mapped scatterlist to give back to the caller.
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*
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* At this point the segments are already laid out by iommu_dma_map_sg() to
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* avoid individually crossing any boundaries, so we merely need to check a
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* segment's start address to avoid concatenating across one.
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*/
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static int __finalise_sg(struct device *dev, struct scatterlist *sg, int nents,
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dma_addr_t dma_addr)
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{
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struct scatterlist *s, *cur = sg;
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unsigned long seg_mask = dma_get_seg_boundary(dev);
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unsigned int cur_len = 0, max_len = dma_get_max_seg_size(dev);
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int i, count = 0;
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for_each_sg(sg, s, nents, i) {
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/* Restore this segment's original unaligned fields first */
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unsigned int s_iova_off = sg_dma_address(s);
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unsigned int s_length = sg_dma_len(s);
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unsigned int s_iova_len = s->length;
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s->offset += s_iova_off;
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s->length = s_length;
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sg_dma_address(s) = DMA_ERROR_CODE;
|
|
sg_dma_len(s) = 0;
|
|
|
|
/*
|
|
* Now fill in the real DMA data. If...
|
|
* - there is a valid output segment to append to
|
|
* - and this segment starts on an IOVA page boundary
|
|
* - but doesn't fall at a segment boundary
|
|
* - and wouldn't make the resulting output segment too long
|
|
*/
|
|
if (cur_len && !s_iova_off && (dma_addr & seg_mask) &&
|
|
(cur_len + s_length <= max_len)) {
|
|
/* ...then concatenate it with the previous one */
|
|
cur_len += s_length;
|
|
} else {
|
|
/* Otherwise start the next output segment */
|
|
if (i > 0)
|
|
cur = sg_next(cur);
|
|
cur_len = s_length;
|
|
count++;
|
|
|
|
sg_dma_address(cur) = dma_addr + s_iova_off;
|
|
}
|
|
|
|
sg_dma_len(cur) = cur_len;
|
|
dma_addr += s_iova_len;
|
|
|
|
if (s_length + s_iova_off < s_iova_len)
|
|
cur_len = 0;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
/*
|
|
* If mapping failed, then just restore the original list,
|
|
* but making sure the DMA fields are invalidated.
|
|
*/
|
|
static void __invalidate_sg(struct scatterlist *sg, int nents)
|
|
{
|
|
struct scatterlist *s;
|
|
int i;
|
|
|
|
for_each_sg(sg, s, nents, i) {
|
|
if (sg_dma_address(s) != DMA_ERROR_CODE)
|
|
s->offset += sg_dma_address(s);
|
|
if (sg_dma_len(s))
|
|
s->length = sg_dma_len(s);
|
|
sg_dma_address(s) = DMA_ERROR_CODE;
|
|
sg_dma_len(s) = 0;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* The DMA API client is passing in a scatterlist which could describe
|
|
* any old buffer layout, but the IOMMU API requires everything to be
|
|
* aligned to IOMMU pages. Hence the need for this complicated bit of
|
|
* impedance-matching, to be able to hand off a suitably-aligned list,
|
|
* but still preserve the original offsets and sizes for the caller.
|
|
*/
|
|
int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
|
|
int nents, int prot)
|
|
{
|
|
struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
|
|
struct iova_domain *iovad = domain->iova_cookie;
|
|
struct iova *iova;
|
|
struct scatterlist *s, *prev = NULL;
|
|
dma_addr_t dma_addr;
|
|
size_t iova_len = 0;
|
|
unsigned long mask = dma_get_seg_boundary(dev);
|
|
int i;
|
|
|
|
/*
|
|
* Work out how much IOVA space we need, and align the segments to
|
|
* IOVA granules for the IOMMU driver to handle. With some clever
|
|
* trickery we can modify the list in-place, but reversibly, by
|
|
* stashing the unaligned parts in the as-yet-unused DMA fields.
|
|
*/
|
|
for_each_sg(sg, s, nents, i) {
|
|
size_t s_iova_off = iova_offset(iovad, s->offset);
|
|
size_t s_length = s->length;
|
|
size_t pad_len = (mask - iova_len + 1) & mask;
|
|
|
|
sg_dma_address(s) = s_iova_off;
|
|
sg_dma_len(s) = s_length;
|
|
s->offset -= s_iova_off;
|
|
s_length = iova_align(iovad, s_length + s_iova_off);
|
|
s->length = s_length;
|
|
|
|
/*
|
|
* Due to the alignment of our single IOVA allocation, we can
|
|
* depend on these assumptions about the segment boundary mask:
|
|
* - If mask size >= IOVA size, then the IOVA range cannot
|
|
* possibly fall across a boundary, so we don't care.
|
|
* - If mask size < IOVA size, then the IOVA range must start
|
|
* exactly on a boundary, therefore we can lay things out
|
|
* based purely on segment lengths without needing to know
|
|
* the actual addresses beforehand.
|
|
* - The mask must be a power of 2, so pad_len == 0 if
|
|
* iova_len == 0, thus we cannot dereference prev the first
|
|
* time through here (i.e. before it has a meaningful value).
|
|
*/
|
|
if (pad_len && pad_len < s_length - 1) {
|
|
prev->length += pad_len;
|
|
iova_len += pad_len;
|
|
}
|
|
|
|
iova_len += s_length;
|
|
prev = s;
|
|
}
|
|
|
|
iova = __alloc_iova(iovad, iova_len, dma_get_mask(dev));
|
|
if (!iova)
|
|
goto out_restore_sg;
|
|
|
|
/*
|
|
* We'll leave any physical concatenation to the IOMMU driver's
|
|
* implementation - it knows better than we do.
|
|
*/
|
|
dma_addr = iova_dma_addr(iovad, iova);
|
|
if (iommu_map_sg(domain, dma_addr, sg, nents, prot) < iova_len)
|
|
goto out_free_iova;
|
|
|
|
return __finalise_sg(dev, sg, nents, dma_addr);
|
|
|
|
out_free_iova:
|
|
__free_iova(iovad, iova);
|
|
out_restore_sg:
|
|
__invalidate_sg(sg, nents);
|
|
return 0;
|
|
}
|
|
|
|
void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
|
|
enum dma_data_direction dir, unsigned long attrs)
|
|
{
|
|
/*
|
|
* The scatterlist segments are mapped into a single
|
|
* contiguous IOVA allocation, so this is incredibly easy.
|
|
*/
|
|
__iommu_dma_unmap(iommu_get_domain_for_dev(dev), sg_dma_address(sg));
|
|
}
|
|
|
|
int iommu_dma_supported(struct device *dev, u64 mask)
|
|
{
|
|
/*
|
|
* 'Special' IOMMUs which don't have the same addressing capability
|
|
* as the CPU will have to wait until we have some way to query that
|
|
* before they'll be able to use this framework.
|
|
*/
|
|
return 1;
|
|
}
|
|
|
|
int iommu_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
|
|
{
|
|
return dma_addr == DMA_ERROR_CODE;
|
|
}
|